Identity federation refers to linking the identity of a person across multiple distinct identity management systems. With identity federation, a person can employ a single set of identity credentials (e.g., username and password) to sign on to multiple network sites operated by different organizations. Each of these network sites integrates its respective authentication system with systems of a federated identity provider. Consequently, once a user is authenticated with the federated identity provider, the user also can become authenticated for each network site that relies upon the federated identity provider.